Question

I have two tables say Table1 and Table2 that contains the following column with which I should join and perform an update a column of Table1 with the value of the same column present in Table2.

Columns for Join condition:

1. Table1.mem_ssn and Table2.ins_ssn
2. Table1.sys_id and Table2.sys_id
3. Table1.grp_id and Table2.grp_id

Column to update:

Table1.dtofhire=Table2.dtofhire

I need a way to bulk update (using single update query without looping) the above mentioned column in Oracle 11G.

Table1 does not contain any key constraint specified since it will be used as a staging table for Data upload.

Please help me out to update the same.

Answer 1

The query that I used to arrive the functionality is seen below

UPDATE table1  T2 
SET    dtofhire = (SELECT Max(dtofhire) AS dtofhire 
           FROM   table2 T1 
           WHERE  T2.mem_ssn = T1.ins_ssn 
              AND T2.sys_id = T1.sys_id 
              AND T2.grp_id = T1.grp_id 
           GROUP  BY ins_ssn, 
               sys_id, 
               grp_id) 
WHERE  ( mem_ssn, sys_id, grp_id ) IN (SELECT ins_ssn, 
                        sys_id, 
                        grp_id 
                     FROM   table2 );